WO2013165430A1 - Ammonia flow modulator to prevent moisture build-up - Google Patents

Ammonia flow modulator to prevent moisture build-up Download PDF

Info

Publication number
WO2013165430A1
WO2013165430A1 PCT/US2012/036402 US2012036402W WO2013165430A1 WO 2013165430 A1 WO2013165430 A1 WO 2013165430A1 US 2012036402 W US2012036402 W US 2012036402W WO 2013165430 A1 WO2013165430 A1 WO 2013165430A1
Authority
WO
WIPO (PCT)
Prior art keywords
passage
ammonia
flow modulator
inlet
ammonia flow
Prior art date
Application number
PCT/US2012/036402
Other languages
French (fr)
Inventor
Jeffrey R. Kelso
Adam C. Lack
Navtej Singh
Original Assignee
International Engine Intellectual Property Company, Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Engine Intellectual Property Company, Llc filed Critical International Engine Intellectual Property Company, Llc
Priority to US14/398,575 priority Critical patent/US20150114486A1/en
Priority to PCT/US2012/036402 priority patent/WO2013165430A1/en
Publication of WO2013165430A1 publication Critical patent/WO2013165430A1/en

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066Selective catalytic reduction [SCR]
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2006Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
    • F01N3/2013Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using electric or magnetic heating means
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066Selective catalytic reduction [SCR]
    • F01N3/208Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00Adding substances to exhaust gases
    • F01N2610/02Adding substances to exhaust gases the substance being ammonia or urea
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00Adding substances to exhaust gases
    • F01N2610/06Adding substances to exhaust gases the substance being in the gaseous form
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00Adding substances to exhaust gases
    • F01N2610/10Adding substances to exhaust gases the substance being heated, e.g. by heating tank or supply line of the added substance
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00Adding substances to exhaust gases
    • F01N2610/10Adding substances to exhaust gases the substance being heated, e.g. by heating tank or supply line of the added substance
    • F01N2610/105Control thereof
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00Adding substances to exhaust gases
    • F01N2610/12Adding substances to exhaust gases the substance being in solid form, e.g. pellets or powder
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00Adding substances to exhaust gases
    • F01N2610/14Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1406Storage means for substances, e.g. tanks or reservoirs
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00Adding substances to exhaust gases
    • F01N2610/14Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1486Means to prevent the substance from freezing
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/12Improving ICE efficiencies
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00Fluid handling
    • Y10T137/6416With heating or cooling of the system
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00Fluid handling
    • Y10T137/6416With heating or cooling of the system
    • Y10T137/6579Circulating fluid in heat exchange relationship
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00Fluid handling
    • Y10T137/6416With heating or cooling of the system
    • Y10T137/6606With electric heating element
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00Fluid handling
    • Y10T137/8593Systems
    • Y10T137/87571Multiple inlet with single outlet
    • Y10T137/87676With flow control

Definitions

  • the present device relates to an ammonia flow modulator (AFM) used in a NOx reduction system to control ammonia gas flow to an exhaust after-treatment system.
  • AFM ammonia flow modulator
  • the device relates to an AFM having features to prevent or reduce moisture buildup in the ammonia flow passages.
  • Compression ignition engines provide advantages in fuel economy, but produce both ⁇ and particulates during normal operation. New and existing regulations continually challenge manufacturers to achieve good fuel economy and reduce the particulates and NO x emissions. Lean-burning engines achieve the fuel economy objective, but the high concentrations of oxygen in the exhaust of these engines yields significantly high
  • One such system is the direct addition of ammonia gas to the exhaust stream. It is an advantage to deliver ammonia directly in the form of a gas, both for simplicity of the flow control system and for efficient mixing of the reducing agent, ammonia, with the exhaust gas.
  • the ammonia dosing is controlled based on any number of readings taken by the system, including exhaust gas temperature, pressure, etc.
  • an aqueous urea solution cannot be dosed at a low engine load since the temperature of the exhaust gas line would be too low for complete conversion of urea to ammonia (and CO 2 ).
  • Direct ammonia gas dosing is not, however, without complications. Trapped ammonia in flow passages, particularly passages in a flow modulator, can hold moisture which may freeze in the passage. Further, moisture which pools or becomes trapped in valves or proximate sensors can significantly upset ammonia dosing schemes. This can lead to failed emission testing for a vehicle and potential revenue losses for a vehicle owner.
  • the present device operates to reduce, if not eliminate, moisture to prevent pooling in modulator passages. This protects the passages and associated valves and sensors. Alternatively, the device may eliminate the freezing issue to prevent blocking and disruption of ammonia flow.
  • a reductant (ammonia) flow modulator comprising a housing, a fluid passage, a first valve, preferably having a precision orifice, positioned within the passage, and an orientation which prevents fluid from pooling in the passage is disclosed and claimed.
  • the passage orientation is preferably substantially vertical to allow gravity to pull fluid from the passage and prevent pooling.
  • a heat source may be positioned within the housing proximate at least one of a fluid inlet, a fluid outlet, or the fluid passage. The heat source prevents freezing of fluid in the passage.
  • the heat source comprises an electric heating element.
  • the heat source comprises an exhaust gas heat exchanger.
  • the ammonia flow modulator may further comprise a second inlet and a second passage fluidly connecting the second inlet to the outlet. This is preferably accomplished by fluidly linking the second passage to the first passage and including a check valve to prevent backflow.
  • a controller coupled to the first valve is used to control ammonia flow.
  • FIG. 1 is a schematic of an exhaust gas NO x reduction (EGNR) system incorporating the start-up cartridge and main cartridges of the present system;
  • EGNR exhaust gas NO x reduction
  • FIG. 2 is a perspective view of the mantel housing containing the main cartridges and the start-up cartridge positioned near but separate from the mantle;
  • FIG. 3 is a right side view of the mantle housing
  • FIG. 4 is a left side view of the mantle housing
  • FIG. 5 is a schematic illustrating one embodiment of an AFM device in accordance with the present disclosure.
  • FIG. 6 is a schematic illustrating another embodiment of an AFM device in accordance with the present disclosure. DETAILED DESCRIPTION
  • FIGS. 1-6 there is illustrated a system for storage and delivery of gaseous ammonia for use in the reduction of NO x in an exhaust gas stream (EGNR).
  • the present flow modulator device generally designated by the numeral 10, is discussed with respect to ammonia flow control, specifically for controlling the supply of ammonia gas to an after-treatment device 30 (FIG. 1) for use in a compression ignition engine (not shown).
  • an after-treatment device 30 for use in a compression ignition engine (not shown).
  • FIGS. 1-6 As the exhaust system of a vehicle, including that of a diesel engine, is well known, it will not be described in detail.
  • a reductant, such as ammonia gas is delivered to the exhaust stream by way of a fluid tubing 50 connected at one end to an ammonia source 40 and at the other end to an injector 60 positioned within the exhaust stream.
  • the ammonia source 40 used for ammonia dosing in the exhaust stream includes a first or start-up unit 12 and a mantle housing 14 having a main unit 16 containing at least one cartridge or canister.
  • the ammonia-containing material loaded into the cartridges of units 12 and 16— also referred to herein as the start-up cartridge 12 and main cartridge 16— is generally in a solid form, such as a compressed powder or granules, and may include any suitable shape for packing into the cartridges, including disks, balls, granules, or a tightly -packed powder.
  • Suitable material for use with the present system include metal-ammine salts, which offer a solid storage medium for ammonia, and represent a safe, practical and compact option for storage and transportation of ammonia.
  • Ammonia may be released from the metal ammine salt by heating the salt to temperatures in the range from 10°C to the melting point to the metal ammine salt complex, for example, to a temperature from 30° to 700°C, and preferably to a temperature of from 100° to 500°C.
  • metal ammine salts useful in the present device include the general formula M(NH 3 ) n X z , where M is one or more metal ions capable of binding ammonia, such as Li, Mg, Ca, Sr, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, etc., n is the coordination number usually 2-12, and X is one or more anions, depending on the valence of M, where representative examples of X are F, CI, Br, I, S0 4 , Mo0 4 , P0 4 , etc.
  • ammonia saturated strontium chloride, Sr(NH 3 )Ci 2 is used.
  • ammonia as the preferred reductant
  • the invention is not limited to such embodiments, and other reductants may be utilized instead of, or in addition to, ammonia for carrying out the inventions disclosed and claimed herein.
  • examples of such other, or additional reductants include, but are not limited to, urea, ammonium carbamate, and hydrogen.
  • the smaller first or start-up unit 12 is positioned separately from the mantle 14 containing the cartridges of main unit 16. Because of its significantly smaller size than that of the main cartridges 16, the first or start-up cartridge 12 can be heated quickly after receiving the appropriate signals from the vehicle's electronics system including an electronic control module (ECM) 18 and Peripheral Interface Module (PIM) 20, which are transmitted to the heating device (not shown). In this manner, the start-up cartridge 12 can start releasing ammonia gas into an after-treatment device 30 and the exhaust stream practically from the initial start-up of the engine, while the main unit 16 is more slowly readied. The flow of ammonia gas from the start-up unit 12 and the main unit 16 is directed through the ammonia flow modulator 10.
  • ECM electronice control module
  • PIM Peripheral Interface Module
  • the flow modulator 10 comprises a housing 42 having an inlet 44 for each of the start-up unit 12 and main unit 16, an outlet 46, passages 48 which connect the inlets 44A,B to the outlet 46, and a control valve 52.
  • the passage 48B from the inlet of the main unit intersects the passage 48A from the start-up unit before or upstream of the control valve 52.
  • a check valve 54 may be used to prevent backflow from the start-up unit passage 48A into the main unit passage 48B.
  • a pressure release valve 56 may be positioned to bypass the control valve 52 to prevent damaging the precision orifice of the control valve 52.
  • the ammonia flow modulator 10 also contains a plurality of circuits and sensors which are designed to facilitate the flow of a sufficient amount of ammonia gas to the exhaust after-treatment device 30.
  • Each passage 48 may include a pressure sensor 62 and/or a temperature sensor 64 to monitor incoming ammonia gas characteristics.
  • An effluent pressure sensor 65 may be positioned downstream of the control valve 52 as well.
  • a controller 70 is preferably coupled to each of the sensors (pressure and temperature) and valves, including the control valve 52 and pressure release valve 56, to orchestrate proper ammonia delivery from each of the start-up unit 12 and the main unit 16.
  • a key aspect of the flow modulator 10 is its ability to prevent blockage due to water freezing in the passages or valves.
  • a heat source 80 is used to maintain the modulator components at a suitable temperature.
  • the heat source 80 may be, for example, an electric heating element, a heat exchanger coupled to the exhaust gas, or any other suitable device for supplying heat to the modulator 10.
  • the heat source 80 is preferably positioned within the housing 42 of the modulator 10, proximate the inlets 44, the passages 48, and the control valve 52.
  • the controller 70 of the modulator 10 can be coupled to the heat source 80 and a temperature sensor to regulate the modulator temperature, as necessary.
  • FIG. 6 An alternate embodiment of the flow modulator 10 is shown in FIG. 6, where the orientation of the modulator passages 48 prevent moisture from becoming trapped within the modulator 10.
  • the passages 48 are generally vertically oriented and straight to take full advantage of gravity to move ammonia through.
  • the lack of "bends" and horizontal surfaces within the passages 48 prevents moisture pooling and keeps them free of fluid during non-use when freezing is most likely to occur.
  • heat sources may also be employed for such embodiments, if desired.
  • the start-up unit 12 can be replenished with ammonia for subsequent use. Positioning the start-up unit 12 outside of the mantle 14 containing the main unit 16, maximizes the heat loss from the start-up unit 12, and also prevents it from being affected by the heat generated from the mantle 14 and main unit 16. Once the cartridge 12 cools to a certain level where the ammonia gas is no longer released from the ammonia-containing material, the material within the unit 12 can be replenished.
  • Replenishing the ammonia-absorbing material can be accomplished in any number of ways, including re-directing a partial flow of ammonia gas released from the main unit 16 due to the drop in temperature to the start-up cartridge, or replenishing by an outside, exterior source of ammonia gas or liquid, or by any other suitable means.
  • the main unit 16 by enclosing the main unit 16 within a mantle housing 14, it is possible to control and maintain the activating temperature required to release the ammonia gas from the material contained within the cartridge or cartridges.
  • the housing 14 acts to minimize the loss of heat to the ambient temperature. Minimizing the temperature loss provides a more efficient and consistent release of ammonia gas from the ammonia- containing material within the main cartridge 16 to an after-treatment device 30.
  • the start-up cartridge 12 is preferably positioned outside of the mantle housing 14 containing the main cartridge units 16 in such a manner that the start-up cartridge is able to cool down quickly without being influenced by any heat generated from the main cartridge unit. In this manner, the ammonia-containing material in the start-up cartridge 12 can be replenished quickly once the cartridge is cooled below the temperature required for sublimation of the material to ammonia gas.
  • Regeneration of the start-up cartridge 12 can be accomplished by directing ammonia gas from the main cartridges 16. Quick regeneration of the start-up cartridge permits it to be ready immediately for the next time the engine is started.
  • the method further comprises a step of maintaining an activating temperature inside the mantle 14 for sufficient release of ammonia gas from the ammonia-containing material within the main cartridge to the after-treatment device 30. In this manner, the method provides for a consistent flow of ammonia into the exhaust stream, and thus, a more efficient and consistent reduction of NO x .

Abstract

An ammonia flow modulator having a housing, a fluid passage, a first valve, preferably having a precision orifice, positioned within the passage, and an orientation which prevents fluid from pooling in the passage is disclosed and claimed. As an added feature, the device may include a heat source positioned within the housing proximate at least one of a fluid inlet, a fluid outlet, and the fluid passage. The heat source may be provided by an electric heating element, an exhaust gas heat exchanger, or any other suitable source. As econd inlet and a second passage fluidly connecting the second inlet to the outlet by fluidly linking the second passage to the first passage and including a check valve to prevent backflow. A controller coupled to the first valve is used to control ammonia flow.

Description

AMMONIA FLOW MODULATOR TO PREVENT MOISTURE BUILD-UP
TECHNICAL FIELD
[0001] The present device relates to an ammonia flow modulator (AFM) used in a NOx reduction system to control ammonia gas flow to an exhaust after-treatment system. Particularly, the device relates to an AFM having features to prevent or reduce moisture buildup in the ammonia flow passages.
BACKGROUND
[0002] Compression ignition engines provide advantages in fuel economy, but produce both Οχ and particulates during normal operation. New and existing regulations continually challenge manufacturers to achieve good fuel economy and reduce the particulates and NOx emissions. Lean-burning engines achieve the fuel economy objective, but the high concentrations of oxygen in the exhaust of these engines yields significantly high
concentrations of NOx as well. Accordingly, the use of NOx reducing exhaust treatment schemes is being employed in a growing number of systems.
[0003] One such system is the direct addition of ammonia gas to the exhaust stream. It is an advantage to deliver ammonia directly in the form of a gas, both for simplicity of the flow control system and for efficient mixing of the reducing agent, ammonia, with the exhaust gas. The ammonia dosing is controlled based on any number of readings taken by the system, including exhaust gas temperature, pressure, etc. In addition, an aqueous urea solution cannot be dosed at a low engine load since the temperature of the exhaust gas line would be too low for complete conversion of urea to ammonia (and CO2).
[0004] Direct ammonia gas dosing is not, however, without complications. Trapped ammonia in flow passages, particularly passages in a flow modulator, can hold moisture which may freeze in the passage. Further, moisture which pools or becomes trapped in valves or proximate sensors can significantly upset ammonia dosing schemes. This can lead to failed emission testing for a vehicle and potential revenue losses for a vehicle owner.
[0005] Accordingly, the present device operates to reduce, if not eliminate, moisture to prevent pooling in modulator passages. This protects the passages and associated valves and sensors. Alternatively, the device may eliminate the freezing issue to prevent blocking and disruption of ammonia flow. SUMMARY
[0006] There is disclosed herein a device which avoids the disadvantages of prior devices while affording additional structural and operating advantages.
[0007] Generally, a reductant (ammonia) flow modulator comprising a housing, a fluid passage, a first valve, preferably having a precision orifice, positioned within the passage, and an orientation which prevents fluid from pooling in the passage is disclosed and claimed. The passage orientation is preferably substantially vertical to allow gravity to pull fluid from the passage and prevent pooling.
[0008] In an alternate embodiment, a heat source may be positioned within the housing proximate at least one of a fluid inlet, a fluid outlet, or the fluid passage. The heat source prevents freezing of fluid in the passage.
[0009] In an embodiment of the device, the heat source comprises an electric heating element. In a distinct embodiment, the heat source comprises an exhaust gas heat exchanger.
[0010] In either embodiment, the ammonia flow modulator may further comprise a second inlet and a second passage fluidly connecting the second inlet to the outlet. This is preferably accomplished by fluidly linking the second passage to the first passage and including a check valve to prevent backflow. A controller coupled to the first valve is used to control ammonia flow.
[0011] These and other embodiments and their advantages can be more readily understood from a review of the following detailed description and the corresponding appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic of an exhaust gas NOx reduction (EGNR) system incorporating the start-up cartridge and main cartridges of the present system;
[0013] FIG. 2 is a perspective view of the mantel housing containing the main cartridges and the start-up cartridge positioned near but separate from the mantle;
[0014] FIG. 3 is a right side view of the mantle housing;
[0015] FIG. 4 is a left side view of the mantle housing;
[0016] FIG. 5 is a schematic illustrating one embodiment of an AFM device in accordance with the present disclosure; and
[0017] FIG. 6 is a schematic illustrating another embodiment of an AFM device in accordance with the present disclosure. DETAILED DESCRIPTION
[0018] Referring to FIGS. 1-6, there is illustrated a system for storage and delivery of gaseous ammonia for use in the reduction of NOx in an exhaust gas stream (EGNR). The present flow modulator device, generally designated by the numeral 10, is discussed with respect to ammonia flow control, specifically for controlling the supply of ammonia gas to an after-treatment device 30 (FIG. 1) for use in a compression ignition engine (not shown). As the exhaust system of a vehicle, including that of a diesel engine, is well known, it will not be described in detail.
[0019] A reductant, such as ammonia gas is delivered to the exhaust stream by way of a fluid tubing 50 connected at one end to an ammonia source 40 and at the other end to an injector 60 positioned within the exhaust stream.
[0020] As shown in FIGS. 2-4, the ammonia source 40 used for ammonia dosing in the exhaust stream includes a first or start-up unit 12 and a mantle housing 14 having a main unit 16 containing at least one cartridge or canister. The ammonia-containing material loaded into the cartridges of units 12 and 16— also referred to herein as the start-up cartridge 12 and main cartridge 16— is generally in a solid form, such as a compressed powder or granules, and may include any suitable shape for packing into the cartridges, including disks, balls, granules, or a tightly -packed powder.
[0021] Suitable material for use with the present system include metal-ammine salts, which offer a solid storage medium for ammonia, and represent a safe, practical and compact option for storage and transportation of ammonia. Ammonia may be released from the metal ammine salt by heating the salt to temperatures in the range from 10°C to the melting point to the metal ammine salt complex, for example, to a temperature from 30° to 700°C, and preferably to a temperature of from 100° to 500°C. Generally speaking, metal ammine salts useful in the present device include the general formula M(NH3)nXz, where M is one or more metal ions capable of binding ammonia, such as Li, Mg, Ca, Sr, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, etc., n is the coordination number usually 2-12, and X is one or more anions, depending on the valence of M, where representative examples of X are F, CI, Br, I, S04, Mo04, P04, etc. Preferably, ammonia saturated strontium chloride, Sr(NH3)Ci2, is used. While embodiments using ammonia as the preferred reductant are disclosed, the invention is not limited to such embodiments, and other reductants may be utilized instead of, or in addition to, ammonia for carrying out the inventions disclosed and claimed herein. Examples of such other, or additional reductants include, but are not limited to, urea, ammonium carbamate, and hydrogen.
[0022] As noted above, in order to use the ammonia gas in the treatment of NOx in an exhaust system, it is necessary to apply a sufficient amount of heat to the cartridges of units 12 and 16, and thus the ammonia-containing material, in order to release the ammonia into its useful gaseous form. Heating the cartridges of units 12, 16 may be accomplished through use of any suitable heating device, such as heating jacket or mantle (not shown) surrounding the cartridges. In this regard, during the initial start-up of an engine, there is generally insufficient heat generated to activate the ammonia-containing material, especially material stored in the main unit 16 within the mantle housing 14. Therefore, in order to jump-start the release of ammonia gas into the after-treatment device 30 and the exhaust stream, the smaller first or start-up unit 12 is positioned separately from the mantle 14 containing the cartridges of main unit 16. Because of its significantly smaller size than that of the main cartridges 16, the first or start-up cartridge 12 can be heated quickly after receiving the appropriate signals from the vehicle's electronics system including an electronic control module (ECM) 18 and Peripheral Interface Module (PIM) 20, which are transmitted to the heating device (not shown). In this manner, the start-up cartridge 12 can start releasing ammonia gas into an after-treatment device 30 and the exhaust stream practically from the initial start-up of the engine, while the main unit 16 is more slowly readied. The flow of ammonia gas from the start-up unit 12 and the main unit 16 is directed through the ammonia flow modulator 10.
[0023] The flow modulator 10 comprises a housing 42 having an inlet 44 for each of the start-up unit 12 and main unit 16, an outlet 46, passages 48 which connect the inlets 44A,B to the outlet 46, and a control valve 52. As shown in FIG. 5, the passage 48B from the inlet of the main unit intersects the passage 48A from the start-up unit before or upstream of the control valve 52. A check valve 54 may be used to prevent backflow from the start-up unit passage 48A into the main unit passage 48B. Also, a pressure release valve 56 may be positioned to bypass the control valve 52 to prevent damaging the precision orifice of the control valve 52.
[0024] The ammonia flow modulator 10 also contains a plurality of circuits and sensors which are designed to facilitate the flow of a sufficient amount of ammonia gas to the exhaust after-treatment device 30. Each passage 48 may include a pressure sensor 62 and/or a temperature sensor 64 to monitor incoming ammonia gas characteristics. An effluent pressure sensor 65 may be positioned downstream of the control valve 52 as well. A controller 70 is preferably coupled to each of the sensors (pressure and temperature) and valves, including the control valve 52 and pressure release valve 56, to orchestrate proper ammonia delivery from each of the start-up unit 12 and the main unit 16.
[0025] A key aspect of the flow modulator 10 is its ability to prevent blockage due to water freezing in the passages or valves. In a first embodiment, shown in FIG. 5, a heat source 80 is used to maintain the modulator components at a suitable temperature. The heat source 80 may be, for example, an electric heating element, a heat exchanger coupled to the exhaust gas, or any other suitable device for supplying heat to the modulator 10. The heat source 80 is preferably positioned within the housing 42 of the modulator 10, proximate the inlets 44, the passages 48, and the control valve 52. The controller 70 of the modulator 10 can be coupled to the heat source 80 and a temperature sensor to regulate the modulator temperature, as necessary.
[0026] An alternate embodiment of the flow modulator 10 is shown in FIG. 6, where the orientation of the modulator passages 48 prevent moisture from becoming trapped within the modulator 10. The passages 48 are generally vertically oriented and straight to take full advantage of gravity to move ammonia through. The lack of "bends" and horizontal surfaces within the passages 48 prevents moisture pooling and keeps them free of fluid during non-use when freezing is most likely to occur. For added reliability, heat sources may also be employed for such embodiments, if desired.
[0027] Once the ammonia gas is completely released from the ammonia-containing material contained within the start-up unit 12, and the system temperature has reached a sufficient level to activate the main unit 16, the start-up unit 12 can be replenished with ammonia for subsequent use. Positioning the start-up unit 12 outside of the mantle 14 containing the main unit 16, maximizes the heat loss from the start-up unit 12, and also prevents it from being affected by the heat generated from the mantle 14 and main unit 16. Once the cartridge 12 cools to a certain level where the ammonia gas is no longer released from the ammonia-containing material, the material within the unit 12 can be replenished. Replenishing the ammonia-absorbing material can be accomplished in any number of ways, including re-directing a partial flow of ammonia gas released from the main unit 16 due to the drop in temperature to the start-up cartridge, or replenishing by an outside, exterior source of ammonia gas or liquid, or by any other suitable means.
[0028] In addition, by enclosing the main unit 16 within a mantle housing 14, it is possible to control and maintain the activating temperature required to release the ammonia gas from the material contained within the cartridge or cartridges. The housing 14 acts to minimize the loss of heat to the ambient temperature. Minimizing the temperature loss provides a more efficient and consistent release of ammonia gas from the ammonia- containing material within the main cartridge 16 to an after-treatment device 30.
[0029] The start-up cartridge 12 is preferably positioned outside of the mantle housing 14 containing the main cartridge units 16 in such a manner that the start-up cartridge is able to cool down quickly without being influenced by any heat generated from the main cartridge unit. In this manner, the ammonia-containing material in the start-up cartridge 12 can be replenished quickly once the cartridge is cooled below the temperature required for sublimation of the material to ammonia gas.
[0030] Regeneration of the start-up cartridge 12 can be accomplished by directing ammonia gas from the main cartridges 16. Quick regeneration of the start-up cartridge permits it to be ready immediately for the next time the engine is started. The method further comprises a step of maintaining an activating temperature inside the mantle 14 for sufficient release of ammonia gas from the ammonia-containing material within the main cartridge to the after-treatment device 30. In this manner, the method provides for a consistent flow of ammonia into the exhaust stream, and thus, a more efficient and consistent reduction of NOx.

Claims

CLAIMS What is claimed is:
1. An ammonia flow modulator comprising: a housing having a first inlet and an outlet; a first passage fluidly connecting the first inlet to the outlet; and a first valve positioned within the passage for controlling a flow of ammonia to the outlet; wherein the first passage is oriented such that gravity prevents fluid from being retained therein.
2. The ammonia flow modulator of Claim I, wherein the first passage is entirely linear.
3. The ammonia flow modulator of Claim I, wherein the first inlet of the housing is positioned superiorly to the outlet of the housing.
4. The ammonia flow modulator of Claim 1, further comprising a heat source within the housing.
5. The ammonia flow modulator of Claim 4, wherein the heat source comprises an electric heating element.
6. The ammonia flow modulator of Claim 4, wherein the heat source comprises a heat exchanger.
7. The ammonia flow modulator of Claim 6, wherein the heat exchanger is fluidly coupled to an engine exhaust flow.
8. The ammonia flow modulator of Claim 1, further comprising a second passage connecting a second inlet to the first passage.
9. The ammonia flow modulator of Claim 8, wherein the second passage is oriented such that gravity prevents fluid from being retained therein.
10. The ammonia flow modulator of Claim 9, wherein the second passage is substantially vertical.
11. A reductant flow modulator comprising: a housing having a first inlet and an outlet; a first passage fluidly connecting the first inlet to the outlet; and a first valve positioned within the passage for controlling a flow of reductant to the outlet; wherein the first passage is oriented such that gravity prevents fluid from being retained therein.
12. The reductant flow modulator of claim 11, wherein the reductant is ammonia.
PCT/US2012/036402 2012-05-03 2012-05-03 Ammonia flow modulator to prevent moisture build-up WO2013165430A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US14/398,575 US20150114486A1 (en) 2012-05-03 2012-05-03 Ammonia flow modulator to prevent moisture build-up
PCT/US2012/036402 WO2013165430A1 (en) 2012-05-03 2012-05-03 Ammonia flow modulator to prevent moisture build-up

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2012/036402 WO2013165430A1 (en) 2012-05-03 2012-05-03 Ammonia flow modulator to prevent moisture build-up

Publications (1)

Publication Number Publication Date
WO2013165430A1 true WO2013165430A1 (en) 2013-11-07

Family

ID=49514683

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2012/036402 WO2013165430A1 (en) 2012-05-03 2012-05-03 Ammonia flow modulator to prevent moisture build-up

Country Status (2)

Country Link
US (1) US20150114486A1 (en)
WO (1) WO2013165430A1 (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19946900A1 (en) * 1999-06-22 2000-12-28 Bosch Gmbh Robert Complex system dosing and mixing urea and air, used for nitrogen oxide conversion in vehicle exhaust purification systems, is integrated into or onto single plastic or metal block
US20070283685A1 (en) * 2004-11-10 2007-12-13 Wolfgang Ripper Metering System And Method For Operating A Metering System
US20090308466A1 (en) * 2006-12-20 2009-12-17 Rainer Haeberer Device for supplying fluid media at low temperatures
US20100086467A1 (en) * 2008-10-06 2010-04-08 Amminex A/S Release of Stored Ammonia at Start-Up
US20120020857A1 (en) * 2010-07-21 2012-01-26 Isada Raymond Upano Dosing system having recirculation heating and vacuum draining
US20120073264A1 (en) * 2010-09-27 2012-03-29 Yongxiang Li Reductant dosing system

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3710984A (en) * 1968-11-25 1973-01-16 Gillette Co Dispensing package of the pressurized type
US4915687A (en) * 1989-02-17 1990-04-10 Sivert George A Needleless injection port arrangement
JPH0784662B2 (en) * 1989-12-12 1995-09-13 アプライドマテリアルズジャパン株式会社 Chemical vapor deposition method and apparatus
US6063350A (en) * 1997-04-02 2000-05-16 Clean Diesel Technologies, Inc. Reducing nox emissions from an engine by temperature-controlled urea injection for selective catalytic reduction
KR101241922B1 (en) * 2005-06-22 2013-03-11 어드밴스드 테크놀러지 머티리얼즈, 인코포레이티드 Apparatus and process for integrated gas blending
DE102007042409A1 (en) * 2007-09-06 2009-03-12 Robert Bosch Gmbh Exhaust after-treatment arrangement with reducing agent storage and method for aftertreatment of exhaust gases
JP5139765B2 (en) * 2007-10-12 2013-02-06 ボッシュ株式会社 Control device and control method for reducing agent supply system
US8459012B2 (en) * 2008-11-19 2013-06-11 Caterpillar Inc. Method for purging a dosing system
US8122710B2 (en) * 2008-12-01 2012-02-28 International Engine Intellectual Property Company, Llc Thermal management of urea dosing components in an engine exhaust after-treatment system
DE102009017497A1 (en) * 2009-04-16 2010-10-21 Airbus Deutschland Gmbh Water supply module
US8359833B2 (en) * 2009-12-23 2013-01-29 Caterpillar Inc. Method for introducing a reductant into an exhaust stream

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19946900A1 (en) * 1999-06-22 2000-12-28 Bosch Gmbh Robert Complex system dosing and mixing urea and air, used for nitrogen oxide conversion in vehicle exhaust purification systems, is integrated into or onto single plastic or metal block
US20070283685A1 (en) * 2004-11-10 2007-12-13 Wolfgang Ripper Metering System And Method For Operating A Metering System
US20090308466A1 (en) * 2006-12-20 2009-12-17 Rainer Haeberer Device for supplying fluid media at low temperatures
US20100086467A1 (en) * 2008-10-06 2010-04-08 Amminex A/S Release of Stored Ammonia at Start-Up
US20120020857A1 (en) * 2010-07-21 2012-01-26 Isada Raymond Upano Dosing system having recirculation heating and vacuum draining
US20120073264A1 (en) * 2010-09-27 2012-03-29 Yongxiang Li Reductant dosing system

Also Published As

Publication number Publication date
US20150114486A1 (en) 2015-04-30

Similar Documents

Publication Publication Date Title
US9028783B2 (en) Cold start startup unit for urea-based systems
US9512760B2 (en) Aftertreatment system implementing low-temperature SCR
CN104847459B (en) Internal combustion engine
US10695719B2 (en) Producing ammonium carbamate and reducing nitrogen oxides
US20160061083A1 (en) System for injecting reactants in an exhaust line
KR20100127266A (en) Scr system for purifying exhaust gases in nox
US9140166B1 (en) Reductant dosing system
EP2662549A1 (en) Method and system for purifying the exhaust gases of a combustion engine.
US8549849B2 (en) Insulated main NH3 cartridge system with separate start-up unit
US9394822B2 (en) Emission control system including an oxidation catalyst and selective catalytic reduction catalyst
WO2013133802A1 (en) Ammonia canister having integral electric heating elements
JP2009209896A (en) Nitrogen oxide reducing device
JP5310804B2 (en) Exhaust gas purification device for internal combustion engine
WO2012134519A1 (en) Common manifold and modular canister arrangement
US20150114486A1 (en) Ammonia flow modulator to prevent moisture build-up
US20140325964A1 (en) Ammonia gas pressure booster
WO2013160712A1 (en) System and method for treating nitrogen oxides contained in exhaust gases
CN110546355B (en) Dosing module for an aftertreatment system of an internal combustion engine
EP3837432B1 (en) Assembly for reducing the nitrogen oxides circulating in an exhaust line of an internal combustion engine
WO2012134518A1 (en) Ammonia canister connection device
WO2014003718A1 (en) Modular exhaust treatment system
WO2013109273A1 (en) Ammonia storage system
KR101316272B1 (en) Cartridge type selective catalytic reduction system
WO2013162526A1 (en) Biasing of ammonia lines to facilitate canister removal and insertion
WO2013133790A2 (en) Rear wall canister coupling

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12875850

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 14398575

Country of ref document: US

122 Ep: pct application non-entry in european phase

Ref document number: 12875850

Country of ref document: EP

Kind code of ref document: A1